1. Field of the Invention
The present invention relates to a door lock, and more particularly to a plug assembly for a door lock and having a positioning capability for against torsion.
2. Description of the Related Art
With reference to FIGS. 6 and 7, a conventional plug assembly (60) for a door lock comprises a cylindrical barrel portion (60), a plug (62), a driving shaft (63) and an adjusting cap (64). The plug (62) is mounted rotatably within the cylindrical barrel portion (60), extends out from the rear end of the cylindrical barrel portion (60) and is connected with the driving shaft (63) with the adjusting cap (64). The driving shaft (63) is connected to a driving blade in a doorknob.
However, because the conventional plug assembly (60) does not have any positioning and limiting structure, the plug (62) is easily overturned, and a large torsion will be applied to the driving blade to cause the driving blade being damaged. In addition, before the conventional plug assembly (60) is assembled to the doorknob, the plug (62) can be rotated freely relative to the cylindrical barrel portion (61). If the plug (62) is rotated at 180° when the plug assembly (60) is assembled onto the doorknob, as shown in FIG. 8, the plug (62) is in an incorrect assembling direction and cannot be rotated. Consequently, this will cause inconvenient of assembling the door lock.